/*
 *
 *  *    Copyright 2020-2021 Luter.me
 *  *
 *  *    Licensed under the Apache License, Version 2.0 (the "License");
 *  *    you may not use this file except in compliance with the License.
 *  *    You may obtain a copy of the License at
 *  *
 *  *      http://www.apache.org/licenses/LICENSE-2.0
 *  *
 *  *    Unless required by applicable law or agreed to in writing, software
 *  *    distributed under the License is distributed on an "AS IS" BASIS,
 *  *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  *    See the License for the specific language governing permissions and
 *  *    limitations under the License.
 *
 */

package com.luter.heimdall.webflux.web;

import com.luter.heimdall.core.context.WebRequestHolder;
import org.slf4j.Logger;
import org.springframework.http.HttpCookie;
import org.springframework.http.HttpHeaders;
import org.springframework.http.server.reactive.ServerHttpRequest;

import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.util.Optional;

import static org.slf4j.LoggerFactory.getLogger;

/**
 * Reactive web request 功能实现
 * <p>
 * 实现基于 reactive web 的请求处理功能
 *
 * @author luter
 */
public class ReactiveWebRequestHolder implements WebRequestHolder {

    /**
     * The constant log.
     */
    private static final transient Logger log = getLogger(ReactiveWebRequestHolder.class);
    private static final String IP_UNKNOWN = "unknown";
    private static final String IP_LOCAL = "127.0.0.1";
    private static final String IPV6_LOCAL = "0:0:0:0:0:0:0:1";
    private static final int IP_LEN = 15;
    /**
     * The Request.
     */
    private ServerHttpRequest request;

    /**
     * Instantiates a new Reactive web request holder.
     *
     * @param request the request
     */
    public ReactiveWebRequestHolder(ServerHttpRequest request) {
        if (null == request) {
            throw new IllegalArgumentException("ReactiveWebRequestHolder can not be null ");
        }
        this.request = request;
    }

    @Override
    public String getCookieValue(String name) {
        final HttpCookie httpCookie = request.getCookies().getFirst(name);
        log.debug("[getCookieValue]::name = [{}]", name);
        return null != httpCookie ? httpCookie.getValue() : null;
    }

    @Override
    public String getHeaderValue(String name) {
        log.debug("[getHeaderValue]::name = [{}]", name);
        return request.getHeaders().getFirst(name);
    }

    @Override
    public String getQueryValue(String name) {
        log.debug("[getQueryValue]::name = [{}]", name);
        return request.getQueryParams().getFirst(name);
    }

    @Override
    public String getRequestURI() {
        log.debug("[getRequestURI]::");
        return request.getURI().getPath();
    }

    @Override
    public String getQueryString() {
        log.debug("[getQueryString]::");
        return null;
    }

    @Override
    public String getMethod() {
        log.debug("[getMethod]::");
        return request.getMethodValue();
    }

    @Override
    public String getRemoteIp() {
        log.debug("[getRemoteIp]::");
//        final InetSocketAddress address = request.getRemoteAddress();
//        if (null != address) {
//            final String hostAddress = address.getAddress().getHostAddress();
//            log.debug("[getRemoteIp]:: ip address = [{}]", hostAddress);
//            return hostAddress;
//        }
        final String ipAddress = getIpAddress(request);
        return "0:0:0:0:0:0:0:1".equals(ipAddress) ? "127.0.0.1" : ipAddress;
    }

    /**
     * 获取用户真实IP地址，不直接使用request.getRemoteAddr();的原因是有可能用户使用了代理软件方式避免真实IP地址,
     * <p>
     * 可是，如果通过了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP值，究竟哪个才是真正的用户端的真实IP呢？
     * 答案是取X-Forwarded-For中第一个非unknown的有效IP字符串。
     * <p>
     * 如：X-Forwarded-For：192.168.1.110, 192.168.1.120, 192.168.1.130,
     * 192.168.1.100
     * <p>
     * 用户真实IP为： 192.168.1.110
     */
    public static String getIpAddress(ServerHttpRequest request) {

//        request.getURI().getHost();

        HttpHeaders headers = request.getHeaders();
        String ipAddress = headers.getFirst("x-forwarded-for");
        if (ipAddress == null || ipAddress.length() == 0 || IP_UNKNOWN.equalsIgnoreCase(ipAddress)) {
            ipAddress = headers.getFirst("Proxy-Client-IP");
        }
        if (ipAddress == null || ipAddress.length() == 0 || IP_UNKNOWN.equalsIgnoreCase(ipAddress)) {
            ipAddress = headers.getFirst("WL-Proxy-Client-IP");
        }
        if (ipAddress == null || ipAddress.length() == 0 || IP_UNKNOWN.equalsIgnoreCase(ipAddress)) {
            ipAddress = Optional.ofNullable(request.getRemoteAddress())
                    .map(address -> address.getAddress().getHostAddress())
                    .orElse("");
            if (IP_LOCAL.equals(ipAddress) || IPV6_LOCAL.equals(ipAddress)) {
                // 根据网卡取本机配置的IP
                try {
                    InetAddress inet = InetAddress.getLocalHost();
                    ipAddress = inet.getHostAddress();
                } catch (UnknownHostException e) {
                    // ignore
                }
            }
        }

        // 对于通过多个代理的情况，第一个IP为客户端真实IP,多个IP按照','分割
        if (ipAddress != null && ipAddress.length() > IP_LEN) {
            int index = ipAddress.indexOf(",");
            if (index > 0) {
                ipAddress = ipAddress.substring(0, index);
            }
        }
        return ipAddress;
    }

    /**
     * 获取客户端端口
     */
    public static Integer getPort(ServerHttpRequest request) {
        final InetSocketAddress remoteAddress = request.getRemoteAddress();
        if (null != remoteAddress) {
            return remoteAddress.getPort();
        }

        return -1;
    }

    /**
     * Gets request.
     *
     * @return the request
     */
    public ServerHttpRequest getRequest() {
        return request;
    }

    /**
     * Sets request.
     *
     * @param request the request
     * @return the request
     */
    public ReactiveWebRequestHolder setRequest(ServerHttpRequest request) {
        if (null == request) {
            throw new IllegalArgumentException("ReactiveWebRequestHolder can not be null ");
        }
        this.request = request;
        return this;
    }
}
